A steady-state analysis of the isothermal multilayer film casting process has been conducted. The effects of the rheological properties of each layer and the processing conditions on the fluid velocity and stress profiles and the film tension were studied. The fluids were modeled using a modified Giesekus model, which is capable of predicting a wide range of rheological behavior. The mechanics of multilayer film casting were found to depend on the shape and magnitude of the elongational viscosities of the fluid components at the deformation rates of the process. The layer with a much larger elongational viscosity dominates the overall flow behavior, even if its thickness fraction is small.